package thinkingInJava.enumerated;
// page 606 职责链
//: enumerated/PostOffice.java
//Modeling a post office.
import java.util.*;
import static thinkingInJava.YTool.YPrint.*;

class Mail {
	// The NO's lower the probability of random selection:
	enum GeneralDelivery {YES,NO1,NO2,NO3,NO4,NO5}
	enum Scannability {UNSCANNABLE,YES1,YES2,YES3,YES4}
	enum Readability {ILLEGIBLE,YES1,YES2,YES3,YES4}
	enum Address {INCORRECT,OK1,OK2,OK3,OK4,OK5,OK6}
	enum ReturnAddress {MISSING,OK1,OK2,OK3,OK4,OK5}
	GeneralDelivery generalDelivery;
	Scannability scannability;
	Readability readability;
	Address address;
	ReturnAddress returnAddress;
	static long counter = 0;
	long id = counter++;
	public String toString() { return "Mail " + id; }
	public String details() {
		return toString() +
				", General Delivery: " + generalDelivery +
				", Address Scanability: " + scannability +
				", Address Readability: " + readability +
				", Address Address: " + address +
				", Return address: " + returnAddress;
	}
	// Generate test Mail:
	public static Mail randomMail() {
		Mail m = new Mail();
		m.generalDelivery= Enums.random(GeneralDelivery.class);
		m.scannability = Enums.random(Scannability.class);
		m.readability = Enums.random(Readability.class);
		m.address = Enums.random(Address.class);
		m.returnAddress = Enums.random(ReturnAddress.class);
		return m;
	}
	public static Iterable<Mail> generator(final int count) {
		return new Iterable<Mail>() {
			int n = count;
			public Iterator<Mail> iterator() {
				return new Iterator<Mail>() {
					public boolean hasNext() { return n-- > 0; }
					public Mail next() { return randomMail(); }
					public void remove() { // Not implemented
						throw new UnsupportedOperationException();
					}
				};
			}
		};
	}
}

public class PostOffice {
	enum MailHandler {
		GENERAL_DELIVERY {
			boolean handle(Mail m) {
				switch(m.generalDelivery) {
				case YES:
					print("Using general delivery for " + m);
					return true;
				default: return false;
				}
			}
		},
		MACHINE_SCAN {
			boolean handle(Mail m) {
				switch(m.scannability) {
				case UNSCANNABLE: return false;
				default:
					switch(m.address) {
					case INCORRECT: return false;
					default:
						print("Delivering "+ m + " automatically");
						return true;
					}
				}
			}
		},
		VISUAL_INSPECTION {
			boolean handle(Mail m) {
				switch(m.readability) {
				case ILLEGIBLE: return false;
				default:
					switch(m.address) {
					case INCORRECT: return false;
					default:
						print("Delivering " + m + " normally");
						return true;
					}
				}
			}
		},
		RETURN_TO_SENDER {
			boolean handle(Mail m) {
				switch(m.returnAddress) {
				case MISSING: return false;
				default:
					print("Returning " + m + " to sender");
					return true;
				}
			}
		};
		abstract boolean handle(Mail m);
	}
	static void handle(Mail m) {
		for(MailHandler handler : MailHandler.values())
			if(handler.handle(m))
				return;
		print(m + " is a dead letter");
	}
	public static void main(String[] args) {
		for(Mail mail : Mail.generator(10)) {
			print(mail.details());
			handle(mail);
			print("*****");
		}
	}
} /* Output:
Mail 0, General Delivery: NO2, Address Scanability: UNSCANNABLE, Address Readability: YES3, Address Address: OK1, Return address: OK1
Delivering Mail 0 normally
 *****
Mail 1, General Delivery: NO5, Address Scanability: YES3, Address Readability: ILLEGIBLE, Address Address: OK5, Return address: OK1
Delivering Mail 1 automatically
 *****
Mail 2, General Delivery: YES, Address Scanability: YES3, Address Readability: YES1, Address Address: OK1, Return address: OK5
Using general delivery for Mail 2
 *****
Mail 3, General Delivery: NO4, Address Scanability: YES3, Address Readability: YES1, Address Address: INCORRECT, Return address: OK4
Returning Mail 3 to sender
 *****
Mail 4, General Delivery: NO4, Address Scanability: UNSCANNABLE, Address Readability: YES1, Address Address: INCORRECT, Return address: OK2
Returning Mail 4 to sender
 *****
Mail 5, General Delivery: NO3, Address Scanability: YES1, Address Readability: ILLEGIBLE, Address Address: OK4, Return address: OK2
Delivering Mail 5 automatically
 *****
Mail 6, General Delivery: YES, Address Scanability: YES4, Address Readability: ILLEGIBLE, Address Address: OK4, Return address: OK4
Using general delivery for Mail 6
 *****
Mail 7, General Delivery: YES, Address Scanability: YES3, Address Readability: YES4, Address Address: OK2, Return address: MISSING
Using general delivery for Mail 7
 *****
Mail 8, General Delivery: NO3, Address Scanability: YES1, Address Readability: YES3, Address Address: INCORRECT, Return address: MISSING
Mail 8 is a dead letter
 *****
Mail 9, General Delivery: NO1, Address Scanability: UNSCANNABLE, Address Readability: YES2, Address Address: OK1, Return address: OK4
Delivering Mail 9 normally
 *****
 *///:~
